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Commit 659d73ad authored by Thomas Abraham's avatar Thomas Abraham Committed by Kukjin Kim
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gpio/samsung: Add device tree support for EXYNOS4 



As gpio chips get registered, a device tree node which represents the
gpio chip is searched and attached to it. A translate function is also
provided to convert the gpio specifier into actual platform settings
for pin function selection, pull up/down and driver strength settings.

Signed-off-by: default avatarThomas Abraham <thomas.abraham@linaro.org>
Acked-by: default avatarGrant Likely <grant.likely@secretlab.ca>
[kgene.kim@samsung.com: fixed build error]
Signed-off-by: default avatarKukjin Kim <kgene.kim@samsung.com>
parent f983575a

Documentation/devicetree/bindings/gpio/gpio-samsung.txt

0 → 100644
+40 −0
Original line number Diff line number Diff line 
Samsung Exynos4 GPIO Controller



Required properties:

- compatible: Compatible property value should be "samsung,exynos4-gpio>".



- reg: Physical base address of the controller and length of memory mapped

  region.



- #gpio-cells: Should be 4. The syntax of the gpio specifier used by client nodes

  should be the following with values derived from the SoC user manual.

     <[phandle of the gpio controller node]

      [pin number within the gpio controller]

      [mux function]

      [pull up/down]

      [drive strength]>



  Values for gpio specifier:

  - Pin number: is a value between 0 to 7.

  - Pull Up/Down: 0 - Pull Up/Down Disabled.

                  1 - Pull Down Enabled.

                  3 - Pull Up Enabled.

  - Drive Strength: 0 - 1x,

                    1 - 3x,

                    2 - 2x,

                    3 - 4x



- gpio-controller: Specifies that the node is a gpio controller.

- #address-cells: should be 1.

- #size-cells: should be 1.



Example:



	gpa0: gpio-controller@11400000 {

		#address-cells = <1>;

		#size-cells = <1>;

		compatible = "samsung,exynos4-gpio";

		reg = <0x11400000 0x20>;

		#gpio-cells = <4>;

		gpio-controller;

	};

drivers/gpio/gpio-samsung.c

+72 −0
Original line number Diff line number Diff line
@@ -24,6 +24,9 @@ 
#include <linux/interrupt.h>

#include <linux/sysdev.h>

#include <linux/ioport.h>

#include <linux/of.h>

#include <linux/slab.h>

#include <linux/of_address.h>



#include <asm/irq.h>
@@ -2374,6 +2377,63 @@ static struct samsung_gpio_chip exynos4_gpios_3[] = { 
#endif

};



#if defined(CONFIG_ARCH_EXYNOS4) && defined(CONFIG_OF)

static int exynos4_gpio_xlate(struct gpio_chip *gc, struct device_node *np,

			      const void *gpio_spec, u32 *flags)

{

	const __be32 *gpio = gpio_spec;

	const u32 n = be32_to_cpup(gpio);

	unsigned int pin = gc->base + be32_to_cpu(gpio[0]);



	if (WARN_ON(gc->of_gpio_n_cells < 4))

		return -EINVAL;



	if (n > gc->ngpio)

		return -EINVAL;



	if (s3c_gpio_cfgpin(pin, S3C_GPIO_SFN(be32_to_cpu(gpio[1]))))

		pr_warn("gpio_xlate: failed to set pin function\n");

	if (s3c_gpio_setpull(pin, be32_to_cpu(gpio[2])))

		pr_warn("gpio_xlate: failed to set pin pull up/down\n");

	if (s5p_gpio_set_drvstr(pin, be32_to_cpu(gpio[3])))

		pr_warn("gpio_xlate: failed to set pin drive strength\n");



	return n;

}



static const struct of_device_id exynos4_gpio_dt_match[] __initdata = {

	{ .compatible = "samsung,exynos4-gpio", },

	{}

};



static __init void exynos4_gpiolib_attach_ofnode(struct samsung_gpio_chip *chip,

						 u64 base, u64 offset)

{

	struct gpio_chip *gc =  &chip->chip;

	u64 address;



	if (!of_have_populated_dt())

		return;



	address = chip->base ? base + ((u32)chip->base & 0xfff) : base + offset;

	gc->of_node = of_find_matching_node_by_address(NULL,

			exynos4_gpio_dt_match, address);

	if (!gc->of_node) {

		pr_info("gpio: device tree node not found for gpio controller"

			" with base address %08llx\n", address);

		return;

	}

	gc->of_gpio_n_cells = 4;

	gc->of_xlate = exynos4_gpio_xlate;

}

#elif defined(CONFIG_ARCH_EXYNOS4)

static __init void exynos4_gpiolib_attach_ofnode(struct samsung_gpio_chip *chip,

						 u64 base, u64 offset)

{

	return;

}

#endif /* defined(CONFIG_ARCH_EXYNOS4) && defined(CONFIG_OF) */



/* TODO: cleanup soc_is_* */

static __init int samsung_gpiolib_init(void)

{
@@ -2455,6 +2515,10 @@ static __init int samsung_gpiolib_init(void) 
				chip->config = &exynos4_gpio_cfg;

				chip->group = group++;

			}

#ifdef CONFIG_CPU_EXYNOS4210

			exynos4_gpiolib_attach_ofnode(chip,

					EXYNOS4_PA_GPIO1, i * 0x20);

#endif

		}

		samsung_gpiolib_add_4bit_chips(exynos4_gpios_1, nr_chips, S5P_VA_GPIO1);
@@ -2467,6 +2531,10 @@ static __init int samsung_gpiolib_init(void) 
				chip->config = &exynos4_gpio_cfg;

				chip->group = group++;

			}

#ifdef CONFIG_CPU_EXYNOS4210

			exynos4_gpiolib_attach_ofnode(chip,

					EXYNOS4_PA_GPIO2, i * 0x20);

#endif

		}

		samsung_gpiolib_add_4bit_chips(exynos4_gpios_2, nr_chips, S5P_VA_GPIO2);
@@ -2479,6 +2547,10 @@ static __init int samsung_gpiolib_init(void) 
				chip->config = &exynos4_gpio_cfg;

				chip->group = group++;

			}

#ifdef CONFIG_CPU_EXYNOS4210

			exynos4_gpiolib_attach_ofnode(chip,

					EXYNOS4_PA_GPIO3, i * 0x20);

#endif

		}

		samsung_gpiolib_add_4bit_chips(exynos4_gpios_3, nr_chips, S5P_VA_GPIO3);